package com.vote.www.utils;

import java.security.MessageDigest;

public class MD5Util {
    public final static String MD5(String s) {
        char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};       
        try {
            byte[] btInput = s.getBytes();
            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            // 使用指定的字节更新摘要
            mdInst.update(btInput);
            // 获得密文
            byte[] md = mdInst.digest();
            // 把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 密码加密
     * @param string
     * @return
     */
    public static String getMD5(String string){
        String md5 = MD5(string);
        return md5.substring(string.length())+md5.substring(0,string.length());
    }

    /**
     * 输入密码和加密后的密码 校验
     * @param password  输入密码
     * @param md5_password  加密后的密码
     * @return  true相等 false不相等
     */
    public static boolean checkPassword(String password, String md5_password){
        if(getMD5(password).equals(md5_password)){
            return true;
        }
        return false;
    }
    public static void main(String[] args) {
        System.out.println(MD5Util.MD5("20121221"));
        System.out.println(MD5Util.MD5("加密"));

        System.out.println(MD5("adfsdflj"));
        System.out.println(getMD5("adfsdflj"));

        if(checkPassword("adfsdflj","47224B226B54662A7841D5FFD10343B6")){
            System.out.println("校验成功");
        }else{

            System.out.println("校验失败");
        }
    }
}